# What is “Lightfield tools” plugin for?

I know that in Blender we have a plugin called LightTools (or Lightfield Tools).

It basically adds a grid created from simple mesh, a bunch of lamps, and also some camera. I understand what it is doing, because I can investigate the scene in Blender, but what this is all about?

What are the benefits, usage examples, and what is an overall income from using this script?

• can u tell me how it works or is there any video tutorial on how it works – atek Oct 17 '16 at 3:42

It seems this addon is for rendering Light fields.

From the wiki:

# Description

This script helps setting up rendering of lightfields. It also supports the projection of lightfields with textured spotlights.

# Usage

A simple interface can be accessed in the tool shelf panel in 3D View (T key).

A base mesh has to be provided, which will normaly be a subdivided plane. The script will then create a camera rig and a light rig with adjustable properties. A sample camera and a spotlight will be created on each vertex of the basemesh object axis (maybe vertex normal in future versions).

## Vertex order

The user has to provide the number of cameras or lights in one row in an unevenly spaced grid, the basemesh. Then the right vertex order can be computed as shown below.

  6-7-8
| | |
^ 3-4-5
| | | |
y 0-1-2
x->


There is also a tool to create a basemesh, which is an evenly spaced grid. The row length parameter is taken to construct such a NxN grid. Someone would start out by adding a rectengular plane as the slice plane of the frustrum of the most middle camera of the light field rig. The spacing parameter then places the other cameras in a way, so they have an offset of n pixels from the other camera on this plane.

# What are light fields?

Light fields were originally invented to allow advanced tweaking of a rendered image that would normally only be possible with defined geometry (i.e. a 3D model):

Light fields were introduced into computer graphics in 1996 by Marc Levoy and Pat Hanrahan. Their proposed application was image-based-rendering - computing new views of a scene from pre-existing views without the need for scene geometry.

LightField cameras (also called plenoptic cameras) have a microlense array just in front of the imaging sensor.

Such arrays consist of many microscopic lenses (often in the range of 100,000) with tiny focal lengths (as low as 0.15 mm), and split up what would have become a 2D-pixel into individual light rays just before reaching the sensor.

The resulting raw image is a composition of as many tiny images as there are microlenses. Here’s the fascinating part: every sub-image differs a little bit from its neighbours, because the lightrays were diverted slightly differently depending on the corresponding microlense’s position in the array.

Next, sophisticated software is used to find matching lightrays across all these images. Once it has collected a list of (1) matching lightrays, (2) their position in the microlense array and (3) within the sub-image, the information can be used to reconstruct a sharp 3D model of the scene.

Using this model, you have all of the LightField capabilities at your fingertips: you can define what parts of the image should be in focus or out of focus, define the depth of field, you can set everything in focus, you can shift the perspective or parallax a bit, … You can even use the parallax data to create 3D pictures from a single LightField lense and capture. All of this can be done after you’ve recorded the image.

• Aside from wikipedia link and posting what was on the wiki, there is nothing particularly new here. See OP's question "What are the benefits, usage examples, and what is an overall income from using this script?" – iKlsR Nov 21 '13 at 22:47

By using these tools, in theory, several aspects of review and production can be handled in the post-production stage of development. This is opposed to loosing resources and time when needing slight changes or resolving minor issues that are nevertheless preventative of publishing the final product.

There are three major points that these tools directly attempt to address:

• Artistically the camera direction can be manipulated both for 2D and 3D imagery to affect the focus, subject, tone, etc., similarly to how shot framing and color grading are used. All of these artistic components are heavily dependent on the source material, so re-rendering frames is usually necessary.
• Additionally, in stereoscopic workflow the camera arrangement can be complicated, or the effect intended too arcane to manage without test shots and re-rendering many attempts.
• To tie the two above together and fortify the concept, in computer graphics acquisition of imagery is expensive in terms of both time and man hours. If a frame needs to be re-acquired simply due to a focus, or alignment issue a light field will alleviate the issue by allowing that process to be done in "post", whether the need is artistic, technical, or to correct a flaw.